A head-up display device, which displays vehicle information (speed, mileage, etc.) in front of a windshield to enable a vehicle driver to read the information almost without moving eyes during driving, has been proposed in Patent Literature 1, for example.
A head-up display device 1 for a vehicle is installed in a dashboard of a vehicle 2 as shown in FIG. 1. A display light J projected from the head-up display device 1 for a vehicle is reflected by a windshield 3, and a vehicle driver 3 can recognize a virtual image X by superimposing it on scenery.
In such a head-up display device 1 for a vehicle, a semiconductor laser has been proposed as a light source. Such a device is disclosed in Patent Literature 2, for example. Such a head-up display device 1 is provided with a semiconductor laser, a scanning system, and a screen, and is configured to generate a display image by scanning laser light emitted from a semiconductor laser toward a screen by a scanning system.